Tube for mercury boilers



July 25, 1933. H KERR TUBE FOR MERCURY BOILERS 3 Sheets-Sheet 2 Filed June 5, 1929 Jam W ATTORNEKS July 25, 1933. H. J. KERR TUBE FOR MERCURY BOILERS 3 Sheets-Sheet 3 nnl m 1/1/1114, 116

Filed June 5, 1929 INVENTOR flflw/ .A/M

ATTORNEYS Patented July 25, 1933 j UNITED] STATES ATENT O FICEQ HOWARD a. KERR, F \VESTFIELD, NEV'. .i nzz'sEY, ASSIGNOR To THE BABCOGK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A. CORPORATION on NEWJ BSEY TUBE FOR MitRoUaY BOILERS Application filed Julie 1929. Serial no. 368,538. 1

This invention relates to a vaporgenerating element ofa mercuryboiler and to a mercury boiler comprising a multiplicity of such elements. The vapor generating ele- 5 ments are connected to thelower sides of drums or headers in which a supply of H quid mercury is rovided,'and in which the mercury vapor rom the tubes of the elements is collected after separation from the liquid. The invention will be understood from the descriptionin Connection with the accompanying drawings in which Fig. 1 is a vertical section througha mercury boiler showing the device in position; Fig. 2 isa side view of a group of the tubes; Fig. 3 is a vertical section through one of the tubes; Fig. 4 is a section on an enlarged scale along the line 4P4 ofFig. 2; Fig. .5 is a section on an enlarged scale along the line 55 of Fig. 2; .Fig. 6 is asection on an enlarged scale along theline 6-6 of Fig. 2; Fig. 7 is a section along the line 77 of Fig. 5; Fig. 8 is a side view of a modified group of tubes; Fig. 9 is a vertical section showing afeed tube; Fig. 10 is a section on an enlarged scale along the line 1010 of Fig. 9; Fig. 11 is a section on an enlarged scale alongthe line 11'11of Fig. .9; Fig. 12 is a section on an enlarged scale along the line,12.-12 of 13-13 of Fig. 11; and Fig. 114 is a section along the line-1414 of Fig." v11'.

In the drawings reference character 1 indicates a furnace above which the mercury boiler is located.

row of horizontally disposed headers 2 placed side byside with spaces between them to permit hot products of combustion to pass through; Vapor generating tubes 3 are connected to the lower sides of the'headers 2 and are contacted by the hot gases from the furnace 1. i i

Zigzag baflles 5 are provided between 5 groups or rows of tubes to cause the hot gases to pass across the tubes. These bafiles 5 may be suspended from spacers 6 that are located between the headers 2. A layer of heat insulating material 6"v may be provid- 50 ed along thelower side of headers to pro- Fig. 8; Fig. 13 is. a section along the line The boiler comprises tect thesame'from the intense heat of the furnace.

Connectors? are provided to connect groups of vapor generating tubesto the headers'2. Each connector 7 comprises an upper tubular portion and a lower expanded portion 8, the lower portion being of suflicient size toreceive anumber of vapor generating tubes circumferentiall'y disposed about a center-core. The connectors 7 extend through-the lower Walls of the headers '2 and are connected thereto any convenient manner, as, for example,'by welding,as

indicatedati). v

A circularplate 10 is connected at'a lower end of each connector 7, being preferably welded thereto, as indicated at 11. A number of vapor generating tubes 12 circumfer-.. entially disposed about a. center core 28 have their upper ends extending through holes in theplate lOand may' be connected to this plate by welding, as shownat 18. In each tube 12 is provided a liquid displacer 14, which might advantageously have the form of a twisted fiat strip as shown, to contribute towards causing the rising mixture of mer cury and vapor to sweep along the inside surfaces oi? the tubes 12. When tubes are of a suificiently small-diameter such liquid displacers may be omitted.

. i The lower ends of the tubes 12 extend through the holes in a slightly dished metal plate 15 and are welded therein, as indicated at 16. A tubular 'extension .17 extends up-. wardly through a hole atthe center of the plate15. Radial metal fins "18 (Fig. 6) maybe provided between tubes 12in contact with these tubes toact as spacers. :When these fins-18 projectlbeyond the tubes 12, as shown in Fig. '6, they contribute towards heat transmission to the tubes. be welded in place, as indicated at 18.

An end cap 19 is provided at the lower end of each group of tubes. The; circum fercntial edge of each cap 19 is welded to the edgeof the necked fitting 15, as indi- These fins may cated at 20. The cap 19 is provided witha central hole or recess 21with a conical projection 22 in the bottom thereof. Passages 23 extend from the central hole 21 to positions belowthe ends of the tubes 12.

A feed tube or liquid supply tube 24 has its upper curved end welded in an opening 25 through the connector 7 at a point near the upper side of the lower wall of the header 2.v The tube 24 extends through the circular plate 10 and is welded thereto, as in- I dicatedat 26, and the lower end of the tube- 24 is welded to theextension 17, as. indicated at 27. The tube 24 is preferably provided with bends intermediateits ends, as

indicated in Fig. 9, to provide for expan sion and contraction. The space'between the circumferential vapor tubes12 and the cen. ftral liquid tubes 24 may be advantageously filled with a solid material 28 selected so as not to prevent compensation for expansion and contraction of the tubes, and at the same time limit the heat received by the liquid tubes 24. The construction is opera 'tive and useful without such filling 28, as

the circumferential vapor tubes 12 act as-a shield for the liquid tubes 24.

v In the modification shown in Figs. 3 to 14, the plate 30 the lower end of the' expanded end 8 of the connector 7 is made sufficiently thick to have a reduced upper portion 31 to extend some distance into the expanded portion 8 of the connector 7/ The lower end of the connector 7 is welded to the plate 30, as indicated at 32. In this modification the bundle of tubes 33 are twisted or slightly helical to provide. for

expansion, as shown in Fig. 8, and the up perends of the tubes 33 extend through the plate 30 and are welded in place, as indicated at'34.

The lower ends of the tubes 33 extend through holes in the lower plate 35 and are welded thereto, as indicated at 36. A coni- 'cally shaped cap 37 has its upper edge welded to the plate 35, as indicated at 38, and

use

is provided with a central opening into which the feed tube 24 extends'and is welded in place, as indicated at 40. Passages 41 extend from the central opening 39 to the lower ends of the tubes 33.

The operation is as follows:

Liquid mercury that is introduced into the headers 2 passes downwardly through the feed tubes 24 that are shielded from the hot gases by means ofthe circumferentially disposed vapor tubes 12 or 33, which may be supplemented by mouldable filling mate to the feed tubes 24.

This invention belongs to the class of mercury boilers having dead-end tubes which project downwardly into the furnace and are heated by the hot gases.v Heretofore these tubes have consisted of single tubes provided witlrcores to displace the liquid mercury and to provide for a high velocity of vapor. when formed. By means of the present construction more surface is provided for the generation of vapor in the space occupied by one tube, and by a multiplicity of small tubes arranged in a cylindrical bundle, the

necessity for cores does not exist provided the tubes are of a sufficiently small. diameter. vBy this invention also thermal metal may be used in the'construction of'th'e tubes, which is advantageous considering the high temperatures' employed and the high rates of heat transmission procurable.

Iclaini: q

1. In a mercury boiler, a liquid supply tube, a plurality of vapor'generating tubes around said supply tube, and heat insulating material between 'said supply tube and the other tubes and supported in place by said last named tubes."

2.' In a mercury boiler, a vapor generating 'unit including a liquid supply tube, a plurality of vapor generatingtubes around said supply tube, and fins between the tubes of saidgroup contacting with the vaporgen erating tubes andv means connecting said tubes at adjacent ends.

3. In a mercury boiler, 'a liquid supply tube, a plurality of vapor generating tubes around said supply tube, and mouldable heat insulating material between said supply tube and said vapor generating tubes and supported in place by said last named tubes.

' HOWARD J. KERR. 

